The Identity of the Ship of Theseus: Saussure’s Substance-Free Linguistics

The Ship of Theseus. AI image

The Paradox of Continuity

Among the thought experiments inherited from antiquity, none has more sharply illuminated the problem of identity and persistence than the Ship of Theseus. First recounted by Plutarch in the Life of Theseus, the story presents a simple yet disconcerting thought experiment: the Athenians preserved Theseus’s ship as a monument, periodically replacing its decayed planks until, over time, none of the original materials remained. Was it still the same ship? The paradox has since been revisited by thinkers from Hobbes to Locke, each seeking to locate the ground of identity amid transformation.

For Hobbes, the puzzle deepened when imagining a second ship assembled from the discarded planks. Which, then, is the true ship? Such reflections often revolve around form and substance: whether identity lies in the continuity of matter or in the persistence of structure. Yet, perhaps the problem itself presupposes too much — namely, that there is some intrinsic substance, physical or formal, to which identity must be anchored.

Saussure’s Copernican Turn

Ferdinand de Saussure’s Course in General Linguistics introduced a conceptual revolution that can be brought fruitfully into dialogue with this ancient paradox. By shifting the study of language from substances (sounds or ideas) to relations, Saussure effectively performed a Copernican turn in linguistics.

He famously declared:

“In the language itself, there are only differences. Even more important than that is the fact that, although in general a difference presupposes positive terms between which the difference holds, in a language there are only differences, and no positive terms.”

Language, for Saussure, does not consist of pre-given entities bearing intrinsic properties. Its elements acquire value only by virtue of their position within a system of distinctions. This means that meaning does not reside in any stable essence but in the play of differences that relate one sign to another. For this reason, his theory has often been described as a form of substance-free linguistics.

To clarify this counterintuitive idea, Saussure turned to a non-linguistic analogy:

“If a street is demolished and then rebuilt, we say it is the same street, although there may be physically little or nothing left of the old one. How is it that a street can be reconstructed entirely and still be the same? Because it is not a purely material structure. It has other characteristics which are independent of its bricks and mortar; for example, its situation in relation to other streets.”

The Street and the Ship

The identity of the street, then, is not grounded in material continuity but in positional relations, its coordinates within an urban grid. Its being depends on what surrounds and differentiates it. In this respect, Saussure’s example anticipates the logic of the Ship of Theseus while subtly reconfiguring its terms. For Saussure, identity is not secured by the persistence of form or substance, but by the stability of a position within a system.

If we extend this reasoning, the Ship of Theseus remains “the same” not because its planks preserve some latent essence, nor because its shape endures, but because it continues to occupy a certain differential place within a cultural and linguistic network: the name “Ship of Theseus,” its role in Athenian ritual, its reference within collective memory. The ship’s identity, like that of a linguistic sign, is relational, a function of its coordinates within a structure of differences.

Reinterpreted through this lens, the Ship of Theseus does not endure through the survival of an intrinsic form or an immutable matter. What persists is the differential position of the sign “Ship of Theseus” within a network of cultural and linguistic relations that bestow meaning upon it. Its identity depends on its contrast with other ships, other myths, other civic symbols. As long as this network of distinctions remains intact, the ship continues to be “the same.” When that relational context shifts, when the Athenians no longer recognize it as that ship, its identity dissolves, even if the material vessel endures.

Beyond Substance and Form

Saussure’s linguistics thus invites a third way of conceiving identity, beyond the classical alternatives of substance and form. In the Plutarch–Hobbes lineage, both matter and structure are treated as positive terms whose persistence guarantees sameness. Saussure instead suggests that identity has no positive core at all: it is positional, arising only within a network of differences.

Applied to the Ship of Theseus, this means that the ship’s “being” is not a metaphysical constant but a relational effect. The paradox ceases to puzzle once one abandons the search for an underlying substance. What endures is the difference that situates the ship within a meaningful system, the set of relations that distinguish it from what it is not. In this sense, the ship’s identity, like that of a word, is not in the thing, but between things.

Conclusion

Saussure offers not a solution but a transformation of the Ship of Theseus debate. Where Plutarch and Hobbes asked whether identity resides in matter or in form, Saussure would reply that it resides in neither. Identity is not a property but a position, not what something is, but how it is differentiated. The ship, like the street, like the linguistic sign, persists only so long as the system that sustains its difference persists.

Seen from this perspective, the paradox dissolves not because it is solved but because its presuppositions have shifted. The question of what the ship is gives way to a question of where it stands —within a network of relations, a structure of differences, a language of identity without substance.

References

• Plutarch. (1914). Lives, Volume I: Theseus and Romulus; Lycurgus and Numa; Solon and Publicola (B. Perrin, Trans.). Harvard University Press.
• Hobbes, T. (1655). De Corpore. London.
• Saussure, F. de. (1959). Course in General Linguistics (W. Baskin, Trans.). Philosophical Library.